宏观经济学 第十三章 通货膨胀与失业之间的短期权衡取舍
35 通货膨胀与失业之间的短期权衡取舍(学生)
第35章通货膨胀与失业之间的短期权衡取舍本章是关于经济短期波动的最后一章，通过本章的学习，要求掌握通货膨胀与失业之间在短期与长期内的关系，理解菲利普斯曲线的形状以及影响菲利普斯曲线移动的两个因素，理解减少通货膨胀的短期成本。
在长期中，通货膨胀与失业是不相关的，而短期中，社会面临通货膨胀和失业之间的短期权衡取舍35.1 菲利普斯曲线菲利普斯曲线：一条表示通货膨胀与失业之间短期权衡取舍的曲线菲利普斯曲线说明失业率与通货膨胀率是负相关的，政府要降低失业率，就只能选择一个更高的通货膨胀率。
35.2 菲利普斯曲线的移动：预期的作用长期菲利普斯曲线是一条经过自然失业率的垂线。
失业率=自然失业率-α（实际通货膨胀率-预期通货膨胀率）对于一个既定的预期通货膨胀率，如果实际通货膨胀高于预期通货膨胀，那么失业率就将下降到低于自然失业率。
但在长期中，人们预期到实际存在的通货膨胀，失业就等于自然失业率。
35.3 菲利普斯曲线的移动：供给冲击的作用供给冲击：直接改变企业的成本和价格，使经济中的总供给曲线移动，进而使菲利普斯曲线移动的事件如果企业成本上涨，SRAS向左移动，价格上升，产出与就业下降，通货膨胀率与失业率都上升，菲利普斯曲线就会向右移动。
35.4 降低通货膨胀的代价为了降低通货膨胀率，必须减少货币供给，以减少总需求，短期内产出下降，失业上升。
习题名词解释菲利普斯曲线判断题1、菲利普斯曲线说明了通货膨胀与失业之间的正相关关系。
2、在短期中，总需求增加提高了物价，增加了产量，并减少了失业。
3、价格预期提高使菲利普斯曲线向上移动，并使通货膨胀--失业的权衡取舍不利。
4、货币供给增加提高了通货膨胀，并持久地减少了失业。
5、在长期中失业率不取决于通货膨胀，而且，菲利普斯曲线是一条经过自然失业率的垂线。
6、当实际通货膨胀大于预期通货膨胀时，失业率大于自然失业率。
7、不利的供给冲击，例如，进口石油价格上升使菲利普斯曲线向上移动，并使通货膨胀--失业的权衡取舍不利。
第七讲 通货膨胀与失业之间的短期权衡取舍
一、菲利普斯曲线 Phillips Curve
经济学原理之十:社会面临通货膨胀与失业之间 经济学原理之十 社会面临通货膨胀与失业之间 的权衡取舍。 的权衡取舍。 菲利普斯曲线表明了通货膨胀与失业之间的关系。 菲利普斯曲线表明了通货膨胀与失业之间的关系。 1958年，Phillips在英国《经济学杂志》发表文章， 年 在英国《 在英国 经济学杂志》发表文章， 论述失业率与通货膨胀率之间存在负相关关系。 论述失业率与通货膨胀率之间存在负相关关系。 低失业的年份往往有高通货膨胀， 低失业的年份往往有高通货膨胀，高失业的年份 往往有低通货膨胀。 往往有低通货膨胀。
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失业率= a(实际通货膨胀 实际通货膨胀失业率=自然失业率 - a(实际通货膨胀-预期 通货膨胀） 通货膨胀） 这个式子把失业率与自然失业率、实际通货膨 这个式子把失业率与自然失业率、 胀及预期的通货膨胀联系起来了。 胀及预期的通货膨胀联系起来了。 如果经济有菲利普斯曲线： 如果经济有菲利普斯曲线： = π−1 − 0.5（u -0.06 菲利普斯曲线 π ） 那么该经济的自然失业率为多少？ 那么该经济的自然失业率为多少？要使通货膨 胀减少5%，必须有多少周期性失业？ ，必须有多少周期性失业？ 胀减少
产量
失业 率
15
供给冲击:直接改变企业的成本和销售价格的事件。 供给冲击:直接改变企业的成本和销售价格的事件。 这使经济的总供给曲线移动， 这使经济的总供给曲线移动，进而使菲利普斯曲线 移动。 移动。 在20世纪70年代，当欧佩克削减产量并提高石油世 20世纪70年代， 世纪70年代 界价格时，决策者面临了两次选择。 界价格时，决策者面临了两次选择。扩大总需求以 对付失业，就将进一步提高通货膨胀。 对付失业，就将进一步提高通货膨胀。紧缩总需求 以对付通货膨胀，就将进一步增加失业。 以对付通货膨胀，就将进一步增加失业。
经济学原理 (12.5)--通货膨胀与失业之间的短期权衡取舍、宏观经济政策的六个争论问题-习题答案
Principles of Economics II (Spring 2013)Homework #6(Chapter 33-36, due on June 14th, 2013, submitted out of class)Note: All textbook problem numbers refer to “Problems and Application” part in corresponding chapter, the 6th Chinese/U.S. edition of the textbook.For Chapter 331.Textbook, Chapter 33, #33. a. The current state of the economy is shown in Figure 7. The aggregate-demandcurve and short-run aggregate-supply curve intersect at the same point on thelong-run aggregate-supply curve.Figure 7b. If the central bank increases the money supply, aggregate demand shifts tothe right (to point B). In the short run, there is an increase in output and theprice level.c. Over time, nominal wages, prices, and perceptions will adjust to this new pricelevel. As a result, the short-run aggregate-supply curve will shift to the left.The economy will return to its natural rate of output (point C).d. According to the sticky-wage theory, nominal wages at points A and B areequal. However, nominal wages at point C are higher.e. According to the sticky-wage theory, real wages at point B are lower than realwages at point A. However, real wages at points A and C are equal.f. Yes, this analysis is consistent with long-run monetary neutrality. In the longrun, an increase in the money supply causes an increase in the nominal wage,but leaves the real wage unchanged.2.Textbook, Chapter 33, # 55. a. The statement that "the aggregate-demand curve slopes downward because itis the horizontal sum of the demand curves for individual goods" is false. Theaggregate-demand curve slopes downward because a fall in the price levelraises the overall quantity of goods and services demanded through the wealtheffect, the interest-rate effect, and the exchange-rate effect.b. The statement that "the long-run aggregate-supply curve is vertical becauseeconomic forces do not affect long-run aggregate supply" is false. Economicforces of various kinds (such as population and productivity) do affect long-runaggregate supply. The long-run aggregate-supply curve is vertical because theprice level does not affect long-run aggregate supply.c. The statement that "if firms adjusted their prices every day, then the short-runaggregate-supply curve would be horizontal" is false. If firms adjusted pricesquickly and if sticky prices were the only possible cause for the upward slope ofthe short-run aggregate-supply curve, then the short-run aggregate-supplycurve would be vertical, not horizontal. The short-run aggregate supply curvewould be horizontal only if prices were completely fixed.d. The statement that "whenever the economy enters a recession, its long-runaggregate-supply curve shifts to the left" is false. An economy could enter arecession if either the aggregate-demand curve or the short-runaggregate-supply curve shifts to the left.3.Textbook, Chapter 33, # 88. a. People will likely expect that the new chairman will not actively fight inflationso they will expect the price level to rise.b. If people believe that the price level will be higher over the next year, workerswill want higher nominal wages.c. At any given price level, higher labor costs lead to reduced profitability.d. The short-run aggregate-supply curve will shift to the left as shown in Figure10.Figure 10e. A decline in short-run aggregate supply leads to reduced output and a higherprice level.f. No, this choice was probably not wise. The end result is stagflation, whichprovides limited choices in terms of policies to remedy the situation.Figure 114.Textbook, Chapter 33, # 99. a. If households decide to save a larger share of their income, they must spendless on consumer goods, so the aggregate-demand curve shifts to the left, as shown in Figure 11. The equilibrium changes from point A to point B, so theprice level declines and output declines.b. If Florida orange groves suffer a prolonged period of below-freezingtemperatures, the orange harvest will be reduced. This decline in the naturalrate of output is represented in Figure 12 by a shift to the left in both theshort-run and long-run aggregate-supply curves. The equilibrium changesfrom point A to point B, so the price level rises and output declines.Figure 12Figure 13c. If increased job opportunities cause people to leave the country, the long-runand short-run aggregate-supply curves will shift to the left because there arefewer people producing output. The aggregate-demand curve will also shift tothe left because there are fewer people consuming goods and services. Theresult is a decline in the quantity of output, as Figure 13 shows. Whether theprice level rises or declines depends on the relative sizes of the shifts in theaggregate-demand curve and the aggregate-supply curves.5.Textbook, Chapter 33, #1111. a. If firms become optimistic about future business conditions and increaseinvestment, the result is shown in Figure 18. The economy begins at point Awith aggregate-demand curve AD1 and short-run aggregate-supply curve AS1.The equilibrium has price level P1 and output level Y1. Increased optimismleads to greater investment, so the aggregate-demand curve shifts to AD2.Now the economy is at point B, with price level P2 and output level Y2. Theaggregate quantity of output supplied rises because the price level has risenand people have misperceptions about the price level, wages are sticky, orprices are sticky, all of which cause output supplied to increase.Figure 18b. Over time, as the misperceptions of the price level disappear, wages adjust, orprices adjust, the short-run aggregate-supply curve shifts up to AS2 and theeconomy gets to equilibrium at point C, with price level P3 and output level Y1.The quantity of output demanded declines as the price level rises.c. The investment boom might increase the long-run aggregate-supply curvebecause higher investment today means a larger capital stock in the future,thus higher productivity and output.6.Textbook, Chapter 33, # 1212. Economy B would have a more steeply sloped short-run aggregate-supply curvethan would Economy A, because only half of the wages in Economy B are “sticky.”A 5% increase in the money supply would have a larger effect on output inEconomy A and a larger effect on the price level in Economy B.7.True or false? Keynes's primary message in The General Theory was that short-run economicfluctuations were the result of inadequate aggregate demand that could be corrected by using government policy.TrueFor Chapter 348.Textbook, Chapter 34, # 11. a. When the Fed’s bond traders buy bonds in open-market operations, themoney-supply curve shifts to the right from MS1 to MS2, as shown in Figure 1.The result is a decline in the interest rate.Figure 1 Figure 2b. When an increase in credit card availability reduces the cash people hold, themoney-demand curve shifts to the left from MD1 to MD2, as shown in Figure 2.The result is a decline in the interest rate.c. When the Federal Reserve reduces reserve requirements, the money supplyincreases, so the money-supply curve shifts to the right from MS1 to MS2, asshown in Figure 1. The result is a decline in the interest rate.d. When households decide to hold more money to use for holiday shopping, themoney-demand curve shifts to the right from MD1 to MD2, as shown in Figure3. The result is a rise in the interest rate.Figure 3e. When a wave of optimism boosts business investment and expands aggregatedemand, money demand increases from MD1 to MD2 in Figure 3. The increasein money demand increases the interest rate.Figure 49.Textbook, Chapter 34, # 22. a. The increase in the money supply will cause the equilibrium interest rate todecline, as shown in Figure 4. Households will increase spending and willinvest in more new housing. Firms too will increase investment spending. Thiswill cause the aggregate demand curve to shift to the right as shown in Figure5.Figure 5b. As shown in Figure 5, the increase in aggregate demand will cause an increasein both output and the price level in the short run (point B).c. When the economy makes the transition from its short-run equilibrium to itslong-run equilibrium, short-run aggregate supply will decline, causing the pricelevel to rise even further (point C).d. The increase in the price level will cause an increase in the demand for money,raising the equilibrium interest rate.e. Yes. While output initially rises because of the increase in aggregate demand,it will fall once short-run aggregate supply declines. Thus, there is no long-runeffect of the increase in the money supply on real output.10.Textbook, Chapter 34, # 3Figure 63. a. When fewer ATMs are available, money demand is increased and themoney-demand curve shifts to the right from MD1 to MD2, as shown in Figure6. If the Fed does not change the money supply, which is at MS1, the interestrate will rise from r1 to r2. The increase in the interest rate shifts theaggregate-demand curve to the left, as consumption and investment fall.b. If the Fed wants to stabilize aggregate demand, it should increase the moneysupply to MS2, so the interest rate will remain at r1 and aggregate demand willnot change.c. To increase the money supply using open market operations, the Fed shouldbuy government bonds.11.Textbook, Chapter 34, #88. a. The initial effect of the tax reduction of $20 billion is to increase aggregatedemand by $20 billion × 3/4 (the MPC) = $15 billion.b. Additional effects follow this initial effect as the added incomes are spent. Thesecond round leads to increased consumption spending of $15 billion × 3/4 =$11.25 billion. The third round gives an increase in consumption of $11.25billion × 3/4 = $8.44 billion. The effects continue indefinitely. Adding them allup gives a total effect that depends on the multiplier. With an MPC of 3/4, themultiplier is 1/(1 – 3/4) = 4. So the total effect is $15 billion × 4 = $60 billion.c. Government purchases have an initial effect of the full $20 billion, becausethey increase aggregate demand directly by that amount. The total effect of anincrease in government purchases is thus $20 billion × 4 = $80 billion. Sogovernment purchases lead to a bigger effect on output than a tax cut does.The difference arises because government purchases affect aggregatedemand by the full amount, but a tax cut is partly saved by consumers, andtherefore does not lead to as much of an increase in aggregate demand.d. The government could increase taxes by the same amount it increases itspurchases.12.Textbook, Chapter 34, # 99. If the marginal propensity to consume is 0.8, the spending multiplier will be 1/(1 – 0.8) = 5. Therefore, the government would have to increase spending by $400/5 = $80 billion to close the recessionary gap.13.Textbook, Chapter 34, 1111. a. Expansionary fiscal policy is more likely to lead to a short-run increase ininvestment if the investment accelerator is large. A large investmentaccelerator means that the increase in output caused by expansionary fiscalpolicy will induce a large increase in investment. Without a large accelerator,investment might decline because the increase in aggregate demand will raisethe interest rate.b. Expansionary fiscal policy is more likely to lead to a short-run increase ininvestment if the interest sensitivity of investment is small. Because fiscalpolicy increases aggregate demand, thus increasing money demand and theinterest rate, the greater the sensitivity of investment to the interest rate thegreater the decline in investment will be, which will offset the positiveaccelerator effect.For Chapter 3514.Textbook, Chapter 35, #11. Figure 8 shows two different short-run Phillips curves depicting these four points.Points A and D are on SRPC1 because both have expected inflation of 3%. Points Band C are on SRPC2 because both have expected inflation of 5%.Figure 815.Textbook, Chapter 35, #4Figure 144. a. Figure 14 shows the economy in long-run equilibrium at point A, which is onboth the long-run and short-run Phillips curves.b. A wave of business pessimism reduces aggregate demand, moving theeconomy to point B in the figure. The unemployment rate rises and theinflation rate declines. If the Fed undertakes expansionary monetary policy, itcan increase aggregate demand, offsetting the pessimism and returning theeconomy to point A, with the initial inflation rate and unemployment rate.c. Figure 15 shows the effects on the economy if the price of imported oil rises.The higher price of imported oil shifts the short-run Phillips curve up fromSRPC1 to SRPC2. The economy moves from point A to point C, with a higherinflation rate and higher unemployment rate. If the Fed engages inexpansionary monetary policy, it can return the economy to its originalunemployment rate at point D, but the inflation rate will be higher. If the Fedengages in contractionary monetary policy, it can return the economy to itsoriginal inflation rate at point E, but the unemployment rate will be higher. Thissituation differs from that in part (b) because in part (b) the economy stayedon the same short-run Phillips curve, but in part (c) the economy moved to ahigher short-run Phillips curve, which gives policymakers a less favorabletrade-off between inflation and unemployment.Figure 1516.Textbook, Chapter 35, #6Figure 166. If the Fed acts on its belief that the natural rate of unemployment is 4%, when thenatural rate is in fact 5%, the result will be a spiraling up of the inflation rate, asshown in Figure 16. Starting from a point on the long-run Phillips curve, with anunemployment rate of 5%, the Fed will believe that the economy is in a recession,because the unemployment rate is greater than its estimate of the natural rate.Therefore, the Fed will increase the money supply, moving the economy along theshort-run Phillips curve SRPC1. The inflation rate will rise and the unemploymentrate will fall to 4%. As the inflation rate rises over time, expectations of inflationwill rise, and the short-run Phillips curve will shift up to SRPC2. This process willcontinue, and the inflation rate will spiral upwards.The Fed may eventually realize that its estimate of the natural rate ofunemployment is wrong by examining the rising trend in the inflation rate.17.Textbook, Chapter 35, #77. a. If wage contracts have short durations, a recession induced by contractionarymonetary policy will be less severe, because wage contracts can be adjustedmore rapidly to reflect the lower inflation rate. This will allow a more rapidmovement of the short-run aggregate-supply curve and short-run Phillipscurve to restore the economy to long-run equilibrium.b. If there is little confidence in the Fed's determination to reduce inflation, arecession induced by contractionary monetary policy will be more severe. Itwill take longer for people's inflation expectations to adjust downwards.c. If expectations of inflation adjust quickly to actual inflation, a recessioninduced by contractionary monetary policy will be less severe. In this case,people's expectations adjust quickly, so the short-run Phillips curve shiftsquickly to restore the economy to long-run equilibrium at the natural rate ofunemployment.18.Textbook, Chapter 35, #9Figure 179. a. As shown in the left diagram of Figure 17, equilibrium output and employmentwill fall. However, the effects on the price level and inflation rate will beambiguous. The fall in aggregate demand puts downward pressure on prices,while the decline in short-run aggregate supply pushes prices up. The diagramon the right side of Figure 17 assumes that the inflation rate rises.b. The Fed would have to use expansionary monetary policy to keep output andemployment at their natural rates. Aggregate demand would have to shift toAD3.c. The Fed may not want to pursue this action because it will lead to a rise in theinflation rate as shown by point C.19.选举周期与经济波动：一个经济某一年的菲利普斯曲线由下列的关系式确定：π = πe - (u - 4%)。
《中级宏观经济学》第13章总供给与通货膨胀和失业之间的短期取舍
CHAPTER 13 Aggregate Supply
slide 2
三种总供给模型
1. 粘性价格模型（sticky-price model） 2. 粘性工资模型（sticky-wage model） 3. 不完全信息模型（imperfect-information model）
Y Y (P P e )
SRAS 关于总供给3模 型意味着 SRAS
曲线和该方程
CHAPTER 13 Aggregate Supply
slide 18
If there is a sudden increase in the price level, the farmer doesn’t know if it is a change in overall prices or just the price of wheat. Typically, she will assume that it is a relative price increase and will therefore increase the production of wheat. Most suppliers will tend to make this mistake. To sum up, the notion that output deviates from its natural level when the price level deviates from the expected price level is captured by:
slide 12
Y = F(L)
L = Ld (W/P) Labor, L
An increase in the price level, reduces the real wage for a given
10通货膨胀与失业之间的短期权衡取舍——菲利普斯曲线
六：政策含义 货币政策是否应该按规则制定？ 货币政策是否应该以零通货膨胀为目标？
总结和练习 ●短期菲利普斯曲线描述了总需求变动时，失业和 通货膨胀之间的负相关关系。 ●长期菲利普斯曲线是在自然率时的一条垂直线。 ●短期菲利普斯曲线会由于预期通货膨胀的变化而 移动。 ●短期菲利普斯曲线会由于供给冲击而移动。 ●反通胀的代价取决于人们通胀预期的变化速度。
例1、假设经济中的自然失业率是5%，根 据以下情况，请画出相关的菲利普斯曲 线，并标出每种情况在图中的位置。
实际通货膨胀率 A B C D 5% 3% 5% 3% 预期通货膨胀率 3% 5% 5% 3%
例2、假设经济处于长期均衡。 A 假设人们由于对经济前景的悲观而减少 了消费，则对经济有何影响？政府可以 通过政策使经济回到原来的位置吗？ B 假设世界粮食价格上涨，则对经济有何 影响？政府可以通过政策使经济回到原 来的位置吗？
三、短期菲利普斯曲线与预期通货膨胀 1、方程式
失业率=自然失业率-a（实际通货膨胀-预期通货膨胀）
2、短期预期通货膨胀不变，失业与实际通货膨 胀负相关 3、预期通货膨胀变化，菲利普斯曲线移动 4、预期通货膨胀等于实际通货膨胀，菲利普斯 曲线垂直。 5、短期到长期的过程 现实的检验：六十年代到七十年代的美国经济
四、菲利普斯曲线的移动：供给冲击 1、供给冲击：直接改变企业的成本和价格， 使经济中的总供给曲线移动，进而使菲 利普斯曲线移动的事件。 2、不利的供给冲击：使菲利普斯曲线右移， 更加不利。
五、降低通货膨胀的代价 1、牺牲率：在通货膨胀减少一个百分点的 过程中每年产量损失的百分点。 2、短期：反通胀的牺牲大 3、理性预期与无代价的反通胀 理性预期 政策与理性预期的形成 理性预期使菲利普斯曲线移动
通货膨胀与失业之间的短期权衡取舍宏观经济政策的六个争论问题PPT课件
失业与通货膨胀 Unemployment and Inflation
通胀与失业的关系这一话题吸引了过去半个世 纪最重要的一些经济学家的注意力。 The relationship between inflation and unemployment is a topic that has attracted attention of some of the most important economists of the last half-century.
(a) AD－AS模型 The Model of AD and AS
(b) 菲利普斯曲线 The Phillips Curve
Price Level
106 102
短期AS
Short-run Inflation Rate
AS
(percent per
B
高AD
year)
6
B
A
High AD
0 7,500
(unemployment is 7%)
低AD Low AD
Quantity
of Output
8,000
(unemployment
is 4%)
2
0
4
(output is
8,000)
A
菲利普斯曲线 Phillips curve
7
Unemployment
(output is Rate (percent)
7,500)
通货膨胀与失业之间的短期权衡取舍宏观经济政策的六个 争论问题
通货膨胀与失业之间的短期权衡取舍宏观经济政策的六个 争论问题
失业与通货膨胀：长期 Unemployment and Inflation: The
宏观经济学 第十三章 失业与通货膨胀
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（二）二战后的理论
1.乘数—加速数模型
乘数原理：回忆投资乘数 Y ki K
（一）菲利普斯曲线三种表达方式
1.原始的菲利普斯曲线
1958年，菲利普斯根据1861-1957年间英国失业率与 货币工资增长率的统计资料提出。 该曲线表明失业率与货币工资增长率之间存在交替关 系： 失业率较低时，货币工资增长率较高； 失业率较高时，货币工资增长率较低。
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2.修改的菲利普斯曲线
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二、通货膨胀的影响
（一）通货膨胀的惯性
——导致通货膨胀的初始原因消失了，通货膨胀也可以 自行持续下去。
原因：通货膨胀预期的存在 工人要求提高W
生产成本上升，P进一步上涨
W进一步提高
10
通货膨胀的持续性
AS2 P4 P3 P1 P0 AS1 AD2
工资增加导致更多消费 ，P进一步上升
AD0
工资上升使AS上移，P AD1 进一步上涨 总需求冲击使P上涨
真实性。
2.对收入再分配的影响 降低固定收入阶层实际收入水平 对储蓄者不利：考虑实际利率 通胀使债权人受损而债务人受益 将居民财富转移到政府手中
3.通货膨胀的产出效应 未预期到的通货膨胀、非平衡的通货膨胀会 对产出带来影响。
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三、菲利普斯曲线和预期理论
引言：回忆需求拉动通货膨胀 P↑，且y↑ P↑，就业↑ P↑，u↓
补充1：对通货膨胀率和失业率组合的理解
2023年曼昆宏观经济学总供给与通货膨胀和失业之间的短期权衡
曼昆《宏观经济学》（第6、7版）第13章总供应与通货膨胀和失业之间旳短期权衡复习笔记跨考网独家整顿最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参照书等内容，更有跨考考研历年辅导旳经济学学哥学姐旳经济学考研经验，从前辈中获得旳经验对初学者来说是宝贵旳财富，这或许能帮你少走弯路，躲开某些陷阱。
如下内容为跨考网独家整顿，如您还需更多考研资料，可选择经济学一对一在线征询进行征询。
1．总供应模型（1）长期总供应模型在长期，价格具有弹性，总供应曲线是垂直旳，总需求旳移动影响物价水平，经济旳产出一直保持在其自然率水平上，如图13-1所示。
图13-1 长期旳总供应曲线（2）三种短期总供应模型三种短期总供应模型都认为市场旳某种不完善性使经济旳产出背离其自然率水平，成果短期总供应曲线向右上方倾斜，而不是垂直旳，总需求曲线旳移动引起产出水平临时背离其自然率。
得出了相似旳短期总供应方程式：(),0e Y Y P P αα=+->其中，Y 为产出，Y 为自然产出，P 为物价水平，e P 为预期旳物价水平，参数α表达产出对未预期到旳物价水平变动旳反应程度，1/α是总供应曲线旳斜率。
这个方程式阐明，当物价水平背离预期旳物价水平时，产出背离其自然率水平。
①黏性工资模型在黏性工资模型中，在短期内假设劳动市场失灵，名义工资具有黏性，不能随劳动旳供求状况立即调整。
未预期到旳物价水平上涨不会立即影响名义工资，则实际工资（/W P ）下降，更低旳实际工资使企业雇佣更多劳动力，从而导致产出增长。
如图13-2所示，图（a ）表达劳动需求曲线。
由于名义工资W 是黏住不变旳，当物价水平从1P 上升届时2P ，实际工资从（1W P ／）下降到（2/W P ），较低旳实际工资使劳动需求量从1L上升到2L 。
图（b ）表达生产函数，当劳动量从1L 上升届时2L ，产出从1Y 增长到2Y 。
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1962 1965 1964 1963
1961
0
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2
3
4
5
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失业率（百分比）
菲利普斯曲线的移动：供给冲击的作用
• 历史事件表明，预期的变动可以使短期菲 利普斯曲线移动。 • 因为总供给的冲击，短期菲利普斯曲线也 会移动。
– 较大的总供给不利变化使失业与通货膨胀之间的短期 替代关系更加严重。 – 供给的不利冲击给决策者在通货膨胀与失业之间更加 不利的权衡取舍。
图5. 预期的通货膨胀如何使短期菲利普斯曲线移动
通货膨 胀率
2. . . . 但在长期中，预期的 通货膨胀上升，而且短期 菲利普斯曲线向右移动。 长期菲利 普斯曲线
B
C
高预期通货膨胀时的 短期菲利普斯曲线
A 1.扩张性政策使经济沿着短期
菲利普斯曲线向上移动……
低预期通货膨胀时的 短期菲利普斯曲线
0
移动。
• 不利的供给冲击给决策者一个较为不利的
通货膨胀与失业之间的权衡取舍。
© 2007 Thomson South-Western
Summary
• 当美联储紧缩货币增长以减少通货膨胀时， 它使经济沿着短期菲利普斯曲线移动。
• 这就引起暂时的高失业。 • 反通货膨胀的代价取决于通货膨胀预期会 多快地下降。
• 菲利普斯曲线说明了短期中出现的通货膨胀 与失业的结合，这种结合的原因是总需求曲 线移动驱使经济沿着短期总供给曲线移动。 • 对物品与劳务的需求量越大，经济中的产量 就越高，物价总水平也就越高。 • 较高的产量带来较低的失业率 。
© 2007 Thomson South-Western
图2. 菲利普斯曲线如何与总需求和总供给模型相关
图3. 长期菲利普斯曲线
通货膨 胀率 长期菲利 普斯曲线
1.当美联储提高 货币供给增长率 时，通货膨胀率 上升……
高通 货膨胀
B
低通 货膨胀
A
2. . . . 但长期中失业仍 维持其自然率水平。
0
自然失业率
失业率
图4. 长期菲利普斯曲线如何与总需求和总供给模型相关
(b) 菲利普斯曲线
(a) 总需求与总供给模型
© 2007 Thomson South-Western
菲利普斯曲线的移动：供给冲击的作用
• 供给冲击——直接改变企业的成本和销售 价格的事件 。 • 这使经济的总供给曲线移动. . . • . . . 进而使菲利普斯曲线移动。
© 2007 Thomson South-Western
图8. 总供给的不利冲击
• 例子包括最低工资法、工会的市场势力、效率工资 的作用，以及寻找工作的有效性。 • 通货膨胀率主要取决于由中央银行控制的货币量增 长。
© 2007 Thomson South-Western
通货膨胀与失业的短期权衡取舍
• 失业与通货膨胀
– 社会面临着通货膨胀与失业之间的短期权衡取 舍。 – 如果政策制定者扩大总需求，他们可以在短期 中减少失业，但这只有以更高的通货膨胀为代 价。 – 如果他们紧缩总需求，他们可以降低通货膨胀， 但这只有以暂时的高失业为代价。
© 2007 Thomson South-Western
理论和证据的一致性
• 问题:古典宏观经济理论预言长期菲利普斯 曲线是垂直的，而证据表明在短期中失业和 通货膨胀之间存在着权衡取舍， 如何将这两点统一起来？
© 2007 Thomson South-Western
短期菲利普斯曲线
• 预期的通货膨胀衡量人们预期物价总水平会 变动多少。 • 在长期中，预期的通货膨胀调整到实际的通 货膨胀变化量。 • 美联储引起未预期到的通货膨胀的能力只在 短期中存在。
自然失业率 失业率
自然率假说的自然试验
• 自然率假说——认为无论通货膨胀率如何， 失业最终要回到其自然率的观点。 • 历史观察数据支持自然率假说。
• 在70年代初期，菲利普斯曲线是稳定的这一 概念破灭了。 • 在70年代和80年代，美国经济高通胀和高失 业并存。
© 2007 Thomson South-Western
第十三章
本章主要内容：
通货膨胀与失业的短期 权衡取舍
• • • •
菲利普斯曲线 菲利普斯曲线的移动：预期的作用 菲利普斯曲线的移动：供给冲击的作用 降低通货膨胀的代价
© 2007 Thomson South-Western
通货膨胀与失业的短期权衡取舍
• 失业与通货膨胀
– 自然失业率取决于劳动市场的各种特点。
沃尔克的反通货膨胀
• 在保罗.沃尔克任美联储主席的20世纪70年 代，通货膨胀被普遍认为是美国最严重的问 题之一。 • 沃尔克成功地降低了通货膨胀（从10％降到 4％），但是以高失业为代价的（1983年的 失业率大约为10％）
© 2007 Thomson South-Western
格林斯潘时代
• 艾伦.格林斯潘担任美联储主席的任期是从有 利的供给冲击开始的。
• 在1986年，欧佩克成员国放弃了他们限制石油 供给的协议。 • 这引起了通货膨胀下降与失业减少。
© 2007 Thomson South-Western
图11. 沃尔克的反通货膨胀
通货膨胀率 （每年百分比）
10
1980 1981
A
1979
8
1982
6
1984 1987 1985
4
C
B
1983
2
1986
0
1
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10 失业率（百分比）
图12. 格林斯潘时代
通货膨胀率 （每年百分比）
10
8
6
1990 1991 1989 1984 1988 1985 1987 2001 1995 1992 2000 1986 1997 1994 1993 1999 2002 1998 1996
4
2
© 2007 Thomson South-Western
菲利普斯曲线
菲利普斯曲线表明了通货膨胀与失业之间 的短期权衡取舍。
© 2007 Thomson South-Western
图1. 菲利普斯曲线
通货膨胀率
（每年百分比）
6
B
2
A 菲利普斯曲线
0
4
7
失业率（百分比）
总需求、总供给与菲利普斯曲线
牺牲率
• 为了降低通货膨胀，一个经济必然忍受一 个高失业和低产量的时期。
• 当美联储对付通货膨胀时，经济沿着短期菲利 普斯曲线向下移动。 • 经济的通货膨胀率下降了，但是以更高的失业 率为代价的。
© 2007 Thomson South-Western
牺牲率
• 牺牲率—— 在通货膨胀减少1％的过程中每 年产量损失的百分比。
• 牺牲率的估算值是5。 • 在1979～1981年期间，为了把通货膨胀从10％
降低到4％，就要求每年牺牲30%的产量。
© 2007 Thomson South-Western
理性预期与无代价地反通货膨胀的可能性
• 理性预期理论认为，当人们预期未来时可以 最好地利用他们拥有的所有信息，包括有关
政府政策的信息。
© 2007 Thomson South-Western
Summary
• By contracting aggregate demand, policymakers can choose a point on the Phillips curve with lower inflation and higher unemployment. • 通过紧缩总需求，决策者可以在菲利普斯 曲线上选择较低通货膨胀与较高失业的一 点。
• 一旦人们预期通货膨胀，使失业率低于自然失业率的唯 一方式就是实际通货膨胀高于预期通货膨胀。
© 2007 Thomson South-Western
短期菲利普斯曲线
失业率 =自然失业率—a(实际通货膨胀－预期通货膨胀）
• 这个式子把失业率与自然失业率、实际通货
膨胀及预期的通货膨胀联系起来了。
© 2007 Thomson South-Western
菲利普斯曲线的移动：供给冲击的作用
• 在20世纪70年代，当欧佩克削减产量并提 高石油世界价格时，决策者面临了两次选 择。
– 扩大总需求以对付失业，就将进一步加剧通货 膨胀。
– 紧缩总需求以对付通货膨胀，就将进一步增加 失业。
© 2007 Thomson South-Western
图9. 70年代的供给冲击
(a) 总需求与总供给模型
物价 水平 通货膨胀率
(每年百分比）
(b) 菲利普斯曲线
短期总供给
106 102 A
B
6
B
高总需求 2 低总需求 0
A
菲利普斯曲线
0 4 7
7,500 8,000 (失业7％） （失业4％）
产量
产量是 8000
产量是 失业率（百分比） 7500
菲利普斯曲线的移动：预期的作用 • 菲利普斯曲线看来为政策制定者提供了一 个可能的通货膨胀——失业结果的菜单。
图6. 60年代的菲利普斯曲线
通货膨胀率 （每年百分比）
10
8
6
1968
4
1967 1966
2
1962 1965 1964 1963
1961
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失业率（百分比）
图7. 菲利普斯曲线的破灭
通货膨胀率 （每年百分比）